56 COME INTO THE GARDEN 



gree of moisture, of warmth, and of air, and any 

 change in this depth seriously affects all three. 

 The removal of even a small amount of earth 

 allows the sun to bake them as well as to draw 

 away the precious moisture from them. And 

 of course it increases the air supply as well — 

 dangerously. 



On the other hand, the addition of earth 

 shuts this off, smothering them; and it upsets, 

 too, the moisture and warmth equilibrium which 

 is so carefully and nicely adjusted. So if trees 

 are to be preserved they must be allowed their 

 places undisturbed. No change of more than 

 two inches either way should be made in the 

 ground around them within the space covered 

 by the full spread of their' branches, which is 

 the space occupied by the spread of their roots 

 — and even this is not desirable. 



I have spoken almost entirely of grading and 

 grade treatment on irregular ground because 

 ground of this character naturally demands 

 more attention than ground which is level. But 

 there are one or two interesting possibilities on 

 even the level tract or plot that are all too sel- 

 dom realized. One of these is the terrace as 

 shown in the first design, page 30, another is 

 the terrace in the rear of the house, page 34. 



There is always a measure of earth to be dis- 



